Magnetism in a chromium jarosite Kagomé lattice KCr3 (OH)6 (SO4)2 (abstract)

The S=3/2 magnetic Cr3+ ions in KCr3 (OH)6 (SO4)2 form a quasi-two-dimensional Kagomé lattice. Susceptibility measurements show a Curie–Weiss temperature of −70 K but specific heat data show a peak at 1.8 K. This depression of the ordering temperature is a result of the extreme frustration of the Kagomé lattice. The change in entropy up to 2.8 K is 0.15 K ln 4. Neutron scattering measurements on a powder specimen put an upper limit of 1 μB on the long-range ordered moments. Constant energy inelastic neutron scattering data with energy transfers of 1.0 and 1.4 meV show a broad peak centered at about 1 Å−1 indicative of strong spin fluctuations at both 0.3 and 10 K.